package watchman;

import java.util.Scanner;

public class Date1 {

	public static void main(String[] args) {
	
		Scanner s=new Scanner(System.in);
		long c1=s.nextLong();
		long c2=s.nextLong();
		long x=(c2-c1)/100;
		int hour=(int) (x/3600);
		int minute=(int) ((x-(hour*3600))/60);
		int second=(int) ((x-(hour*3600))-(minute*60))+1;
		System.out.println(hour+":"+minute+":"+second);
	}

}
